A linear assessment of waveguidability for barotropic Rossby waves in different large-scale flow configurations

Abstract. Topographically forced Rossby waves shape the upper-level waveguide over the midlatitudes, affecting the propagation of transient waves therein, and have been linked to multiple surface extremes. The complex interplay between the forcing and the background flow in shaping the Rossby wave response still needs to be elucidated in a variety of configurations. We propose here an analytical solution of the linearized barotropic vorticity equation to obtain the stationary forced Rossby wave resulting from arbitrary combinations of forcing and background zonal wind. While the onset of barotropic instability might hinder the applicability of the linear framework, we show that the nonlinear wave response can still be retrieved qualitatively from the linearized solution. Examples using single- and double-jet configurations are discussed to illustrate the method and study how the background flow can act as a waveguide for Rossby waves.